In various industrial situations there is a need for a convenient and economical means for moving railcars without attaching the railcars to a traditional locomotive, which then pushes or pulls the railcars to a desired location. Attaching railcars to a traditional locomotive is both inconvenient and time-consuming, and it may require more space than is available in a railroad yard. Additionally, moving a railcar by hand is not an effective solution as it requires substantial manpower and many man hours.
Railcars may also be used for track maintenance, construction, and various other tasks. Therefore, for these applications, the method of attaching railcars to a traditional locomotive is likewise inconvenient and expensive. For example, railcars may be fitted with an apparatus for clearing brush and small trees from a railroad's right of way. In such an instance, the brush clearing apparatus necessarily faces toward the front, and thus any external means of moving the railway car necessarily pushes the railway car from behind. This external means of pushing a railcar, however, is neither convenient nor efficient as an external means such as a traditional locomotive requires additional operational and maintenance costs. Further, to effectively clear brush from the right of way, the railcar fitted with the brush clearing apparatus would need to make more than one pass, and an external means for moving the railway car, such as a locomotive, can not easily and effectively change direction as would be necessary in such a situation.
Various devices have been proposed to address the problem of moving a railcar while allowing for relative ease in changing directions and without requiring an inordinate amount of space. For example, U.S. Pat. No. 5,345,878 describes a method and apparatus and method for moving railway cars using hydraulic motors, which are directly coupled coaxially to the outermost end of a railcar axle, as shown in FIG. 1. Such an arrangement exposes the hydraulic motors to trackside debris (e.g., plant and tree overgrowth, railroad equipment, signage, etc.) as well as other obstructions capable of damaging the motors. Therefore, such a configuration has certain drawbacks.
Others devices for moving a railcar without the use of a locomotive include U.S. Pat. No. 6,343,554, U.S. Pat. No. 3,762,336, U.S. Pat. No. 4,170,945, U.S. Pat. No. 4,867,072. Each of these designs require modification to a railcar wheel and truck assembly. The design proposed here can be installed onto a railcar with no modification to the wheel and truck assembly.
Despite the proposed solutions, there remains a need for an apparatus that is easy to install and remove, is relatively small and inexpensive, and which is confined within the railway car's standard railcar width, thus protecting the apparatus from unnecessary exposure to trackside debris or various other obstructions that could damage the apparatus. Additionally, there remains a need for a device that can be easily retrofitted to a railcar (or standard railcar bogie), thus creating a self-propelled railcar that can operate as a locomotive, either moving independently or moving other railcars, while also being smaller, more mobile and significantly less expensive than a traditional locomotive.